Advances in standards and testbeds for cognitive radio networks: part I [Guest Editorial]

Conventional wireless networks have been designed from a centralized perspective and with a predefined infrastructure, such as cellular networks, but this rigid approach lacks flexibility and adaptability, which are advantages of nextgeneration cognitive radio systems. Thus, it is of paramount importance to design self-configurable cognitive-radio-based networks that are aware of and adaptable to the changing environment to coexist harmoniously with other wireless systems that use a variety of protocols in the same frequency bands. The design of such networks requires the development of a number of new access and transmission technologies to ensure successful coexistence and to avoid causing harmful interference. Cognitive radio technologies such as dynamic spectrum access create huge opportunities for interesting research and development in a wide range of applications including spectrum sensing, navigation, and biomedical/ health.